There is a need for materials for interlayers of golf balls which offer the properties of high resilience and low spin on driver shots and thereby enable a long flight distance. For example, some three-piece golf balls and multi-piece golf balls have been proposed which include a high rigid or high elastic interlayer so as to provide a high launch angle and a low spin and thereby enhance flight distance.
For example, Patent Literature 1 discloses a golf ball including an interlayer which contains a high elastic polyamide resin or a metal-neutralized ethylene-(meth)acrylic acid copolymer. Patent literature 2 also discloses a golf ball including an interlayer which contains a resin composition including an olefin-containing thermoplastic polymer and a diene polymer, and an oxygen-containing inorganic metal compound. Such interlayers provide high rigidity or high elasticity and thereby enable the golf balls to have improved performance such as flight performance.
In order to achieve a low spin on driver shots, a golf ball needs to be highly hard and be firm on the outer layer while becoming softer towards the center so that a recoil force can act effectively. Hence, there are proposed various materials which enable soft compression and sufficient hardness of interlayers at the same time. However, it is generally difficult to achieve high resilience while maintaining soft compression, and also achieve low spin on driver shots. Therefore, improvement is desired.